Mike Thorsen asked "Have you ever made or suggested modifications to an existing game? If so, what game, and how did the mods affect play?"

FGU publilshed my LAND OF THE RISING SUN,a standalone Japanese version of CHIVALRY & SORCERY. At the time, I didn't realize that C&S's mass combat system was based on WRG Ancients (because I never did wargaming). So I dug into the rules and was shocked to find that heavy losses might drive an army to Rout, during which time its speed was faster than it could achieve in a state of fully disciplined advance, faster than its horses could gallop. I decided this didn't make any sense and rewrote the rules. I never got any comments on this, so I suspect that other roleplayers didn't use the rules, and that wargamers didn't look over my modifications. (Let's see, because Japanese armies weren't very disciplined, I also added a couple of Disorganized formations to the standard ones which seemed far too organized.)

When we were playtesting my LANDS OF ADVENTURE (also published by FGU), I decided that the best way to make sure the rules worked was not to be the GM, so I passed out the current version of the rules to the player group and Barry GMed. Occasionally during the game, Barry would say that the rules didn't cover something, or a player would protest, and I'd scribble a hasty correction, then hand out changes at the start of the next game.

I tried changing a few rules when writing GURPS JAPAN (for Steve Jackson Games) and VIKINGS (for Iron Crown Enterprises), but some of these didn't appear in the printed version of the games. I have a list of Errata on GURPS JAPAN that covers most of the major changes between what I wrote and Steve printed.